Major element residence times in humus from a beech forest: The role of element forms and recycling

This study presents the relationship between inputs of elements (especially biominerals), their recycling mechanisms and the average residence time of the major elements in mull humus.In forest ecosystems with generally low element inputs, decomposing leaf litter is an important source of soil nutrients. While the processes and the release speeds of elements, such as C, N and P, are well determined during litter degradation, less is known about elements like Fe, Al, Mg, Mn, Si, Ca, K, or Na, some of which are essential for tree nutrition.The objective of this study was to determine the average residence time of these elements in mull-type humus for 3 different soils: a Dystric Cambisol (S1), Eutric Cambisol (S2) and Rendzic Leptosol (S3), in the same beech grove of the northeast of France and to identify the main mechanisms controlling them.To achieve this goal, the approach used: 1) scanning electron microscope observation of the evolution and recycling of elements during litter degradation; 2) quantification of total inputs and their form (soluble/insoluble) in the litterfall and the contribution of exploitation residues; 3) quantification and evolution of litter stocks; and 4) calculation and comparison of the residence time of the elements according to their form.Calculation of inputs and stocks of elements in humus made it possible to assess the residence time of each elements. The average residence times were between 58.4 and 13.1 y for Fe and Al; 3.3 and 1.6 y for ...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research

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Authors: Yang L, Liu S, Fang W, Chen J, Chen Y Abstract The aim of the present study was to investigate the feasibility of using composite scaffolds of poly(lactic-co-glycolic acid) (PLGA) and bioactive glass (BG) to repair bone defects. PLGA/BG composite scaffolds were prepared by thermally-induced phase separation. Scanning electron microscopy (SEM) was used to study the morphology, and liquid (absolute ethanol) replacement was used to calculate the porosity of the scaffold. The biocompatibility and degradation of the scaffold were determined using human osteosarcoma cell line MG-63 and animal experiments. SEM sh...
Source: Experimental and Therapeutic Medicine - Category: General Medicine Tags: Exp Ther Med Source Type: research
Publication date: Available online 5 December 2019Source: Materials Research BulletinAuthor(s): Jahaziel Amaya, Luis Bobadilla, Lola Azancot, Miguel Centeno, Sonia Moreno, Rafael MolinaAbstractEnhancement of the main physicochemical properties of a natural bentonite was carried out by means of modifications using surfactant, reflux, microwave treatment and, subsequently, the incorporation of AlZr and AlCe species. The evolution of the main changes in each modification stage was evaluated by means of X-ray diffraction, N2 sortometry, scanning microscopy (SEM), NH3-TPD, NH3-DRIFTS and CO adsorption at low temperature. For th...
Source: Materials Research Bulletin - Category: Materials Science Source Type: research
Publication date: Available online 5 December 2019Source: Materials LettersAuthor(s): Kiyoshi Matsuyama, Tomohiro Tsubaki, Takafumi Kato, Tetsuya Okuyama, Hiroyuki MutoAbstractGold nanoparticles (Au NPs) in liquid poly (ethylene glycol) (PEG) were prepared via sputter deposition. This is an easy and simple preparation method for Au NPs , and does not require a chemical reaction or additional stabilizers. A metal-organic framework (MOF), Cu3(BTC)2 (BTC: 1,3,5-benzenetricarboxylic acid), was synthesized in the liquid PEG containing the Au NPs to obtain Au@Cu3(BTC)2. Liquid PEG acted as the capture medium for sputter depositi...
Source: Materials Letters - Category: Materials Science Source Type: research
Publication date: Available online 5 December 2019Source: Materials LettersAuthor(s): Aisha Tanvir, Valeska P. Ting, Stephen J. EichhornAbstractPorous superhydrophobic nanofibrous networks based on cellulose acetate butyrate (CAB) were prepared using electrospinning. The morphology and wettability of the prepared fibrous networks was studied using scanning electron microscopy and static contact angle measurements. The porous nanofiber networks exhibited superhydrophobicity and superoleophilicity with a water contact angle of ∼165° and an oil contact angle of ∼0°. The porous nature of the nanofibres themselv...
Source: Materials Letters - Category: Materials Science Source Type: research
Publication date: Available online 5 December 2019Source: Journal of Materials Science &TechnologyAuthor(s): Jing Chen, Liang Wu, Xingxing Ding, Qiang Liu, Xu Dai, Jiangfeng Song, Bin Jiang, Andrej Atrens, Fusheng PanAbstractHighly oriented Mg-Al layered double hydroxide (LDHs) films were deposited on magnesium alloy AZ31 with different deformation processes by an easy in-situ growth method. The characteristics of the films were investigated by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical, immersion and hydrogen evolution tests. The corrosion protection perfo...
Source: Journal of Materials Science and Technology - Category: Materials Science Source Type: research
CONCLUSIONS: This new method allows operators to correct their own therapy plans and choices, customizing the treatment plan on the actual condition of the patient. Moreover, it makes all the rehabilitation process safer and can reduce the risk of failure, side effects and inconveniences for the patients. PMID: 31799661 [PubMed - in process]
Source: European Review for Medical and Pharmacological Sciences - Category: Drugs & Pharmacology Tags: Eur Rev Med Pharmacol Sci Source Type: research
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Source: Neurophysiologie Clinique - Category: Neuroscience Source Type: research
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Source: Neurophysiologie Clinique - Category: Neuroscience Source Type: research
Publication date: Available online 6 December 2019Source: NeuroscienceAuthor(s): Yijie Zhao, Shuguang Kuai, Theodore P. Zanto, Yixuan KuAbstractThe neural mechanisms associated with the limited capacity of working memory has long been studied, but it is still unclear which neural regions are associated with the precision of visual working memory. Here, an orientation recall task for estimating the trial-wise precision of visual working memory was performed and then repeated two weeks later in an fMRI scanner. Results showed that activity in frontal and parietal regions during working memory maintenance scaled with working ...
Source: Neuroscience - Category: Neuroscience Source Type: research
re AA Abstract Dengue is a re-emerging arbovirus infection of major epidemiological importance. The detection of dengue clusters is an important epidemiological surveillance strategy, contributing to better allocation of control measures and prioritizing areas that are subject to increased risk of transmission. Studies involving human populations with low mobility are scarce, and the current study thus aims to investigate the presence of persistent dengue clusters in the city of Rio de Janeiro, Brazil, in populations with different mobility and immunity. Epidemiological data on dengue were obtained from the Brazil...
Source: Cadernos de Saude Publica - Category: International Medicine & Public Health Authors: Tags: Cad Saude Publica Source Type: research
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